OK, guys. We get it. is not a fad. But a rival to social networking sites? We're having a little trouble with that one. The idea was floated in the latest collection of Second Life usage statistics released by Linden Lab today. The press release stresses the claim that users have spent more than one billion hours in-world, but it also describes a few pieces of information that seem intended to put the 3D virtual world way ahead of the social networking pack in several key areas: